stree.StringTree: Add .parent and .root

Signed-off-by: Jan Lindemann <jan@janware.com>

tools/python/jwutils/stree/StringTree.py

@@ -34,11 +34,13 @@ def cleanup_string(s: str) -> str:
 
 class StringTree: # export
 
-    def __init__(self, path: str, content: str) -> None:
+    def __init__(self, path: str, content: str, parent: StringTree|None=None) -> None:
         slog(DEBUG, f'Constructing StringTree(path="{path}", content="{content}")')
+        self.__parent = parent
         self.children: OrderedDict[str, StringTree] = OrderedDict()
         self.content: Optional[str] = None
         self.__set(path, content)
+
         assert(hasattr(self, "content"))
         #assert self.content is not None
 
@@ -100,13 +102,13 @@ class StringTree: # export
         nibble = components[0]
         rest = '.'.join(components[1:])
         if nibble not in self.children:
-            self.children[nibble] = StringTree('', content=nibble)
+            self.children[nibble] = StringTree('', content=nibble, parent=self)
         if l > 1:
             assert len(rest) > 0
             return self.children[nibble].__set(rest, content=content)
         # last component, a.k.a. leaf
         if content is not None:
-            gc = content if isinstance(content, StringTree) else StringTree('', content=content)
+            gc = content if isinstance(content, StringTree) else StringTree('', content=content, parent=self.children[nibble])
             # Make sure no existing grand child is updated. It would reside too
             # far up in the grand child OrderedDict, we need it last
             if gc.content in self.children[nibble].children:
@@ -189,6 +191,16 @@ class StringTree: # export
         slog(DEBUG, f'Returning value from children {self.children}')
         return self.children[next(reversed(self.children))].content # type: ignore
 
+    @property
+    def parent(self):
+        return self.__parent
+
+    @property
+    def root(self):
+        if self.__parent is None:
+            return self
+        return self.__parent.root
+
     def child_list(self, depth_first: bool=True) -> List[StringTree]:
         if depth_first == False:
             raise Exception("tried to retrieve child list with breadth-first search, not yet implemented")